To understand the problem confronting the inventor at the time the invention was made consideration should be made to the prior art crossover tube heretofore designed for the exhaust nozzle cooling and venting system of the aircraft's nacelle and engine's exhaust nozzle. One end of the crossover tube attaches to the pumping housing which is a rigid body that is attached to the side wall located in an upstream location and the other end of the crossover tube attaches to a downstream end of the side wall closest to the engine's exhaust of the aircraft which is a relatively flexible body. The structure of the aircraft at this location evidences extreme loads which, in turn, causes severe deformation of the sidewalls. The crossover tube must be capable of withstanding these severe distortions and essentially must be capable of substantially 360 degrees of movement in all directions. In any given plane these distortions are relatively large aircraft-to-nozzle relative movements. Obviously, the end of the cross over tube must be capable of movement in the same direction that the aircraft structure flexes so as to avoid premature fatiguing and/or breakage of components.
The problems associated with the prior art crossover tubes can best be seen by referring to FIG. 1, which is a drawing partly in perspective and partly in section showing the prior art crossover tube 2 having opposed spherical ball fittings 4 and 6. These fittings are offset mounted so that their axis is offset relative to the central axis A of crossover tube 2. Each of the spherical ball fittings fit into complementary receivers 8 and 9 and when assembled allow the passage of fluid from one location to another. It is apparent from the foregoing that these prior art crossover tube have relatively limited movement together with other deficiencies that made it incapable of meeting the packaging and the movement requirements for the particular aircraft installation.
A more complex sealing arrangement for the spherical ball was considered for the crossover tube similar to the prior art configuration depicted in FIG. 1, but it required a larger tube length in order to meet the aircraft-to-nozzle relative movement. Not only did it result in a heavier assembly, it still evidenced the problems associated with the less sophisticated sealing arrangement depicted in FIG. 1. One of the major problems associated with these prior art crossover tubes was that it was virtually impossible to assemble the unit which had to fit into a complementary receiving fitting that were already in existence in the system that was hidden from view. Since the receiving tube to which it was to be connected cannot be seen by the person assembling the crossover tube, it is readily apparent that mating the parts were to say the least difficult, if not impossible. Moreover, this problem is acerbated because eight such cross over tubes must uniformly align all at once with eight mating receivers for the assembly to be completed.
The requirement of the aircraft could not tolerate a crossover tube with a limited angular movement and that could not meet the aircraft-to-nozzle relative movement requirements. Nor could it tolerate the longer tube that resulted from a more complex sealing arrangement because of the weight and size problems, given the envelope size of the overall exhaust nozzle configuration and the attendant deficit in engine performance.
I have found that I can obviate the problems noted in the above paragraphs by providing a spring loaded crossover tube that is capable of being connected to a blind connector and that swivels such that it has larger relative nozzle-to-aircraft relative motion than heretofore known designs. In another embodiment bellows are utilized to assure that there is adequate sealing of the crossover tube.